Here are my recommendations:
(1) Have him learn to keep his head upright. He tilts it to the left right at the beginning of his delivery. This can lead to other posture and balance issues later in the delivery which, in turn, lead to an inconsistent release point.
(2) The next thing I’d have him work on is keeping his head more stable and minimizing the posture changes during the delivery. (This is related to (1) above.) If you watch his head in the video, it first moves toward 1B when he takes his rocker step. Then, as he lifts his knee, he tilts it as described above. Then, as he begins his stride, he collapses his back leg and his head takes a big dip. It also moves toward 3B as he ends at the waist to get into a posture he has the strength to maintain through the rest of the stride.
So, adjustments I’d recommend to help stabilize his head - and, therefore, his posture - are to minimize the rocker step to the side and start in a more athletic stance so he doesn’t have to adjust into that during his delivery. Start with the knees bent a tiny bit to reduce the dip. And start with the torso bent forward at the waist a tiny bit to reduce the posture change toward 3B during the delivery.
(3) As others have pointed out, he really needs to stabilize his glove. At foot plant, the glove should be positioned somewhere out front above the front foot. As the shoulders rotate, the glove-side elbow should tuck down below and maybe a little in front of the armpit, and the glove should turn over so the palm faces his chest or face. The glove arm should firm up to create a stable base for the throwing arm to throw against. He should bring his chest to the glove. Keeping the glove up in front will not only provide some front-side stability but it will also allow him to better protect himself (especially his face) from a line drive hit back at him which will be more important next year when he faces the older kids.
Your son is still a young fellow so I wouldn’t get too carried away. But these changes to improve stability will set a good foundation to build upon. Once he’s got these things down, then he can work on other things.